Utility of antenatal clinical factors for prediction of postpartum outcomes in women with gestational diabetes mellitus (GDM)

Background Gestational diabetes mellitus (GDM) is associated with life‐long increased risk of type 2 diabetes: affected women are advised to undergo oral glucose tolerance testing (OGTT) at 6–12 weeks postpartum, then glucose screening every 1–3 years. Aims We investigated whether in women with GDM, antenatal clinical factors predicted postpartum abnormal glucose tolerance and compliance with screening. Materials and methods In women with GDM delivering 2007 to mid‐2009 in a single hospital, antenatal/obstetric data and glucose tests at 6–12 weeks postpartum and during 5.5 years post‐pregnancy were retrospectively collected. Predictors of return for testing and abnormal glucose tolerance were identified using multivariate analysis. Results Of 165 women, 117 (70.9%) returned for 6–12 week postpartum OGTT: 23 (19.6%) were abnormal. Smoking and parity, independent of socioeconomic status, were associated with non‐return for testing. Fasting glucose ≥5.4 mmol/L on pregnancy OGTT predicted both non‐return for testing and abnormal OGTT. During 5.5 years post‐pregnancy, 148 (89.7%) women accessed glucose screening: nine (6.1%) developed diabetes, 33 (22.3%) had impaired fasting glucose / impaired glucose tolerance. Predictors of abnormal glucose tolerance were fasting glucose ≥5.4 mmol/L and 2‐h glucose ≥9.3 mmol/L on pregnancy OGTT (~2.5‐fold increased risk), and polycystic ovary syndrome (~3.4 fold increased risk). Risk score calculation, based on combined antenatal factors, did not improve predictions. Conclusions Antenatal clinical factors were modestly predictive of return for testing and abnormal glucose tolerance post‐pregnancy in women with GDM. Risk score calculations were ineffective in predicting outcomes: risk scores developed in other populations require validation. Ongoing glucose screening is indicated for all women with GDM.